EVALUATING BUMBLEBEES AS POLLINATORS OF 'MISTY' SOUTHERN HIGHBUSH BLUEBERRY GROWING INSIDE PLASTIC TUNNELS

Abstract

Commercial bumblebees pollinating elite hybrid varieties of southern highbush blueberries growing inside plastic tunnels can help increase the market value for blueberry fruit. A bumblebee colony, rotated to a new tunnel every 2-3 days, cross-pollinated two compatible varieties of southern highbush blueberries planted in the approximate ratio of 13 ‘Misty’: 1 ‘Sharpblue’. Colony rotation between tunnels provided more bloom to the bees and eliminated buying a bumblebee colony for each tunnel. Plastic tunnels protected the bumblebees, flowers and developing fruit from freezing during the late winter in southern Mississippi. Bumblebees improved ‘Misty’ fruit production and quality in tunnels, as their visits to flowers substantially enhanced fruit set, ripening, berry size and seed set. Unpollinated ‘Misty’ flowers produced some parthenocarpic fruit. A more efficient cooling system for tunnels, changes in frost protection systems and/or placing colonies outdoors on warmer days will be needed to sustain uninterrupted pollen foraging and pollination by worker bumblebees. Other native bee pollinators such as the megachilid bee, Osmia ribifloris, may soon be available for pollinating blueberries inside tunnels.